[llvm] [llvm][CMake] Introduce LLVM_RUNTIME_<project>_BUILD in CMake (PR #88934)

[Joseph Huber via llvm-commits]

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@@ -208,6 +208,36 @@ foreach(entry ${runtimes})
   list(APPEND RUNTIME_NAMES ${name})
 endforeach()
 
+# Set LLVM_RUNTIME_<project>_BUILD variables if a sub-project is enabled to be built as
+# a runtime.  As with LLVM_TOOL_<project>_BUILD, the LLVM_RUNTIME_<project>_BUILD variables
+# should be not directly used from the CMake configuration command line.
+foreach(proj ${LLVM_SUPPORTED_RUNTIMES})
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jhuber6 wrote:

Don't we need to check for each `LLVM_RUNTIME_TARGETS` if `RUNTIMES_<triple>_LLVM_ENABLE_RUNTIMES` is set?

https://github.com/llvm/llvm-project/pull/88934